Abstract: A sensor system has object detection sensors 4 which are mounted on door mirrors 2 and have a parking space search mode for searching for an object within ranges extending laterally from a vehicle 14, and a vehicle monitoring mode for searching for an object in rear lateral sides of the vehicle 14 by folding and retracting the door mirrors 2; and a control section 7 for causing the object detection sensors 4 to be driven when the vehicle 14 travels at a speed equal to or less than a prescribed value, and for making a search frequency of the object detection sensors 4 higher in the parking space search mode than in the vehicle monitoring mode.